14 NEW YORK STATE MUSEUM 



or 3 miles and are visible from the three railroads. All the ground 

 north of the railroads from Caledonia and Mumford to Leroy has 

 been stream-eroded but the scourways can not be definitely mapped. 

 Similar sinkage features occur on the limestone escarpment west of 

 Syracuse [see p. 24]. 



The altitudes of the channels, always declining eastward, and 

 always successively lower in northward sequence, are sufficiently 

 shown by the topographic contours and numerals of the map 

 The higher channels, those east of Leroy, carried the overflow of 

 the Oatka valley in addition to the supply from the melting ice, 

 from all the stretch of the glacier front east of Batavia. The lower 

 channels, heading in indefinite scourways northwest of Batavia do 

 not suggest any overflow of the Erian waters eastward past the 

 salience north of Batavia. but seem to have carried only the local 

 waters of the melting glacier and the shallowing lake. 



Genesee valley to Irondequoit valley 



The glacial drainage described in the preceding chapter built 

 extensive deltas on the west slope of the Genesee valley. This 

 implies lake waters in the valley with correlating outlets on the 

 east. The deltas have altitudes ranging from about 620 feet down 

 to 580 feet, and at precisely these elevations we find capacious 

 channels leading eastward. These are so clearly shown on the 

 map, plate 2. that little verbal description is necessary. 



It will be seen that the lowest channel, in which lie the villages 

 of Rush. Rochester Junction and Men don, is followed by the 

 Lehisfh Vallev Railroad, and that the Batavia-Canandai^ua 

 branch of the Xew York Central Railroad utilizes for short dis- 

 tances two of the higher channels. The highest cuttings, from 

 700 feet down, lie west of Honeoye Falls [pi. 11] and are mostly 

 cut terraces or shallow scourways in the Onondaga limestone. The 

 irregular surfaces of the bare rock would not at first sight be con- 

 fidently attributed to river work, but comparison and correlation 

 study over the district gives certainty. 



Southwest of Honeoye Falls. 2J miles, is a low cataract and 

 plunge basin known locally as "Dry Pond," produced in the course 

 of the highest channel on the map, at about 680 feet [pi. 12]. 



Like all the lower channels the Rush-Mendon channel is cut in 

 Salina shale. The highest continuous channel passes a mile north 

 of Honeoye Falls with an altitude of 620 feet. Bending to the north- 

 east it continues around the north side of the Victor kame area, 



